@keyframes hover {
  from {
    border-bottom: 1px solid #fff;
  }
  to {
    border-bottom: 1px solid #333;
  }
}
.nav-menu {
  display: flex;
  justify-content: center;
  .menu-item {
    margin: 0 10px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    line-height: 30px;
    font-size: 14px;
    cursor: default;
    border-bottom: 1px solid #fff;
  }
  .menu-item:hover {
    animation: hover .5s linear forwards;
  }
  .active-item {
    border-bottom: 1px solid #333;
  }
}
